Huge lagg on 25 and or 40 man content.

Hi,

I seem to be having an issue when running 25 or 40 mans on Icecrown server. When in the world my ms is around 100 to 300, same for 5 to 15 man content. The second we pull a boss or trash(basically any engage) on 25 man my ping skyrockets to 2.5 or 22k until the fight is over. I do not have any latency problems on any other AAA titles that require online play(CSGO, PoE. HotS, SC2, ESO etc.).

I've tried this so far:

Disable all firewalls and malware and virus software
Cache and error folders deleted
With and without addons(both in and erased from file)
Installed Leatrix latency fix
Flushed DNS
Reset router and connections
With cable and with Wifi
Checked with speedtest when the problem occurs, speedrate is normaly what it's always
Downloaded and installed the Warmane page client for WOTLK


Any tips or ideas that don't require a VPN($$$)? thanks.


Marv